Data QA Engineer

Stadtwerke OELSNITZ/V. GmbH; Greater London; Hybrid; GBP 45,000 - 65,000; Full time

Job summary

Sagacity is a data intelligence company delivering testing and QA for data pipelines across financial services, retail, energy, telecoms and media. The role focuses on testing ETL/ELT processes, validating data quality, and ensuring end-to-end reconciliation across source-to-target pipelines.

You will work with Data Engineers and UAT teams, turning data mappings into test cases and using YAML-driven test frameworks. Hybrid UK-wide role with client-facing duties.

Qualifications

• 2+ years in data testing, data quality, data analytics or QA with data focus.
• Experience: multi-source data environments and agile delivery.
• Client-facing or consulting experience: presenting findings and managing expectations.

Responsibilities

• Write and run SQL to profile and reconcile data across sources.
• Test ETL/ELT pipelines end-to-end and validate data flow.
• Perform data quality checks on completeness, accuracy and schema.
• Do source-to-target reconciliation to verify data integrity.
• Design and maintain test plans from mappings and specs.

Skills

SQL proficiency

ETL/ELT testing

Data quality testing

Reconciliation testing

Analytical mindset

Git basics

Python / PySpark

Databricks Unity Catalog

DBT / Great Expectations / Soda

YAML configurations

AI tooling / LLMs

Tools

Databricks

Unity Catalog

dbt

Great Expectations

Soda

ClickUp

Job description

Location: UKRole Type: Permanent - Full TimeJob Location: Hybrid Working - minimum of 2 days a week in our London office

Sagacity are the data intelligencepeople. Our proposition isbusinesses increase customerengagement and make moreinto the data businesses alreadyhave, and combine it with our data,insight, and action. Think of us asdata co-pilots for sales, marketing,ops, billing, credit and debt - clientstypically see 5x returns within thefirst few months.

Founded in 2005, we are acustomer-centric business witha World Class +95 Net PromoterScore. We believe data should beat the heart of every companyand while we are sector agnostic,primarily our clients are in thetelecoms & media, water, andnot for profit sectors.

We are a purpose led companyand we believe that purposecomes before profit. We workas one team both with clientsand internally, and are trusted todeliver quality in our standardsand in achieving successful clientoutcomes. We are open, honestand communicate in a jargonfree, collaborative way, with all ourteams being agile and curious, andcontinuously learning to achieveour purpose. We believe that ifwe achieve our purpose theneverything else will follow.

ABOUT SAGACITY

Clever with data... combining data,insight, and action to drive value

Key Responsibilities

• Write and run SQL to check, profile and reconcile data across source systems, staging, data warehouse and lakehouse layers
• Test ETL/ELT pipelines end to end, validating transformation logic, business rules and how data flows through each layer (bronze → silver → gold)
• Carry out data quality checks covering completeness, accuracy,duplicates, schema, referential integrity and row volumes
• Perform source-to-target reconciliation and migration parity checks, proving counts, totals and key-level data match the specification
• Write, run and maintain test plans and test cases from data mappings, specifcations and acceptance criteria using Sagacity SPHERE’s YAMLdriven test framework, keeping coverage current as new data sources are onboarded
• Investigate failures and anomalies, distinguish pipeline bugs from source data issues, and log clear, evidenced defects developers can act
• Work directly with clients and UAT teams: explain our testing approach and results, manage expectations on scope, risk and timelines, andbuild trusted relationships
• Collaborate with Data Engineers to agree expected behaviour, review data contracts, and validate fixes before they reach UAT or production
• Manage QA work items in ClickUp, and raise well-specifiedimprovements to SPHERE and our wider QA tooling
• Use AI-assisted tools to speed up test authoring, investigation and documentation, always checking the output against the data

What Sucess Looks Like in the Role

• Client data is reconciled and validated end to end before delivery, with no material data quality issues reaching UAT or production
• Numbers that don’t look right are spotted early, investigated thoroughly and explained clearly
• Developers can reproduce and fix defects from your evidence without back-and-forth
• Clients trust our QA and feel well-informed about what has been tested and why, without needing to ask twice
• Test coverage grows with each delivery increment rather than lagging behind
• Our QA tooling and processes improve because gaps are named and fixed, not just worked around

Role Overview

You will ensure the data we deliver to our clients is right. Sitting between data analysis and quality assurance, you will test the pipelines, data warehouses and lakehouse platforms that drive marketing, billing, credit and debt outcomes for clients across financial services, retail, energy, telecoms & media, water, and the not-for-profit sector.

Working closely with our Data Engineers, Platform Engineer, UAT teams and client stakeholders, you will turn data mappings and specifications into test cases, reconcile data from source to target, investigate anything that doesn’t add up, and explain what you find clearly to both developers and clients. This is a hands-on, client-facing role for someone who enjoys getting stuck into the data.

• Strong SQL: confident writing joins, CTEs, aggregations and window functions to interrogate, profile and reconcile data
• Data pipeline testing: experience testing ETL/ELT processes and data warehouse or lakehouse environments
• Data quality: a solid grasp of how to test completeness, accuracy, duplicates, schema and transformation logic
• Reconciliation and test design: source-to-target reconciliation and writing test cases from data mappings or specs
• Analytical eye: you can tell when the numbers just don’t look right, and work out why
• Engineering basics: comfortable with Git (branching, committing, Python, PySpark or Spark SQL, enough to read pipeline code and trace transformations
• Databricks, including Unity Catalog and medallion (bronze-silver-gold)
• Data testing tools such as dbt tests, Great Expectations or Soda
• YAML-based configuration or structured test frameworks
• Using AI agents and LLMs as a genuine productivity tool

Experience:

• 2+ years in data testing, data quality, data analysis, analytics engineering or a QA role with a strong data focus
• Investigating data issues in a complex, multi-source environment and communicating findings clearly
• Client-facing or consulting experience: presenting findings to non technical audiences, managing expectations and building relationships
• Working directly with development or data engineering teams in an agile or iterative delivery environment

Behaviours:

• Detail-oriented: you notice when numbers don’t add up and follow the thread until you understand why
• Consultative and confident with clients: you explain findings simply, challenge politely and share bad news early, with a plan
• Self-directed: you don’t wait to be told what to test next; you look at the data and ask the right questions finding a developer can act on and a client can understand
• Positive and collaborative: you share knowledge, support peers and improve the process, not just the output
• Organised and adaptable: you manage multiple client streams in parallel and stay calm when priorities shift
• Able to travel throughout the UK and have the right to work in the UK
• Committed to personal development, especially in data platforms and

If you would like to join a unique working environment, with a sociable culture, where work is done a little bit differently – and we believe ‘better’ - then we look forward to hearing from you!

We achieve this through our corevalues:

• One Team
• Quality Delivery
• Agile & Curious
• Open, Honest, Simple Communication

Success in any business isultimately about its people; theirdedication and enthusiasm.

We recognise the value of ourpeople and their commitmentto working together to achievesuccessful outcomes.

At Sagacity, we: believe working with our clients

coach and mentor our clients’ teamsso our data and solutions live on

believe in delivering benefits as we

People at Sagacity